... Geophysicae GPS radio occultation with CHAMP and GRACE: A first look at... – Published: 30 March 2005 Abstract. CHAMP (CHAllenging Minisatellite Payload) and GRACE... humidity. The combined set of CHAMP and GRACE profiles shows excellent... significantly improved in comparison with CHAMP. This allows for the application... GPS/MET are the German CHAMP (Reigber et al., 2005) and... Aplicaciones Cientificas-C). The measurements of CHAMP and SAC-C brought significant progress...., 2004; Wickert et al., 2004b). CHAMP has provided almost continuous occultation... of ∼4 h between each measurement aboard CHAMP and the provision of analysis... studies show a positive impact of CHAMP’s occultation data to the global... occultation measurements in relation to CHAMP before the upcoming missions. In... present first results of combined CHAMP and GRACE occultation data analysis..., filled circles) and those from CHAMP (218 events, crosses) between 28....: GPS occultation with CHAMP and GRACE The first CHAMP and GRACE-B measurements... and local time of the CHAMP descending node (11:27 UTC... ∼1 h/11 days for CHAMP. 2 CHAMP and GRACE orbits 4 CHAMP was launched into an...). 3 First occultations from GRACE and CHAMP measurements The “BlackJack” GPS-Receiver... during this 25-h interval. The CHAMP satellite provided 218 measurements during... global distribution of the relevant CHAMP and GRACE occultation events. The...◦ in relation to 60◦ for CHAMP. Working in nominal mode, the... number of measurements as from CHAMP will be expected. We note... the symmetry axis of the CHAMP occultation antenna is tilted by... to provide and analyze both CHAMP and GRACE data. It consists... has been continuously demonstrated with CHAMP since February 2003. Due to... delay between each measurement aboard CHAMP and the provision of analysis... of the occultation data from CHAMP (Wickert et al., 2004a) and... et al.: GPS occultation with CHAMP and GRACE is performed by... specific humidity profiles from the CHAMP and GRACE refractivities (Heise et... orbit information from the LEO (e.g. CHAMP or GRACE) and GPS satellites... with GPS radio occultation aboard CHAMP, manuscript available: www.arxiv.org.... 2. Rate (or Drift) of the CHAMP (upper panel) and GRACE (lower... for 28 July 2004. The CHAMP drift are unstable in time... Wickert et al. (2002) using CHAMP data. To avoid the application... from 30-s clock solutions from CHAMP and GRACE for 2 GPS radio... et al.: GPS occultation with CHAMP and GRACE The feasibility of... (Wickert et al., 2002). The CHAMP clock shows nearly no drift... primary scientific instruments of the CHAMP mission. The GRACE clock solutions... et al.: GPS occultation with CHAMP and GRACE The vertical refractivity... observed within a larger set of CHAMP data (Wickert et al., 2005... the analyses. 5.3 Comparison of a combined CHAMP/GRACE data set with ECMWF... data set consists of 178 CHAMP and 101 GRACE measurements (279... are analyzed using the single (CHAMP) and zero difference techniques (GRACE... using only the data from CHAMP (Wickert et al., 2004b). Below... is already known from the CHAMP measurements (e.g. Ao et al., 2003... to different characteristics of the CHAMP and GRACE profiles will follow... simulation studies, aerological soundings and CHAMP satellite observations, manuscript available: www... 279 refractivity profiles, derived from CHAMP and GRACE measurements and 6-h ECWMF... 28 and 29 July 2004 (CHAMP/GRACE-ECMWF). 6 Conclusions and outlook... radio occultation measurements aboard the CHAMP and GRACE satellites are presented... for the analysis of the CHAMP and GRACE data, respectively. For... difference techniques. A common set of CHAMP and GRACE refractivity profiles is... similar quality compared to the CHAMP only measurements. Our study has... data. We thank the complete CHAMP and GRACE team with the... the negative refractivity bias using CHAMP observations, J. Geophys. Res., doi:10... overview, in Earth Observation with CHAMP: Results from Three Years in... la Torre Juarez, M., and Yunck, T. P.: CHAMP and SAC-C atmospheric occultation results... Marquardt, C.: Forecast impact experiments with CHAMP GPS radio occultation measurements: Preliminary... in CHAMP orbit determination at GFZ, in Earth Observation with CHAMP: Results... et al.: GPS occultation with CHAMP and GRACE Larsen, G., Lauritsen, K., Rubek, F., and Sørensen, M.: Processing of CHAMP Radio Occultation Data Using GRAS... Software, in Earth Observation with CHAMP: Results from Three Years in..., H., and Wickert, J.: Earth Observation with CHAMP: Results from Three Years in... GPS radio occultation measurements with CHAMP, J. Geophys. Res., 109, D13105, 10... Reigber, C.: GPS radio occultation with CHAMP: Atmospheric profiling utilizing the space..., C., and Ramatschi, M.: Atmospheric sounding with CHAMP: GPS ground station data for..., N.: The radio occultation experiment aboard CHAMP: Operational data processing and validation... Reigber, C.: GPS radio occultation with CHAMP and GRACE: Recent results, in...